| |
| /* pngpread.c - read a png file in push mode |
| * |
| * Last changed in libpng 1.5.23 [July 23, 2015] |
| * Copyright (c) 1998-2015 Glenn Randers-Pehrson |
| * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) |
| * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) |
| * |
| * This code is released under the libpng license. |
| * For conditions of distribution and use, see the disclaimer |
| * and license in png.h |
| */ |
| |
| #include "pngpriv.h" |
| |
| #ifdef PNG_PROGRESSIVE_READ_SUPPORTED |
| |
| /* Push model modes */ |
| #define PNG_READ_SIG_MODE 0 |
| #define PNG_READ_CHUNK_MODE 1 |
| #define PNG_READ_IDAT_MODE 2 |
| #define PNG_READ_tEXt_MODE 4 |
| #define PNG_READ_zTXt_MODE 5 |
| #define PNG_READ_DONE_MODE 6 |
| #define PNG_READ_iTXt_MODE 7 |
| #define PNG_ERROR_MODE 8 |
| |
| void PNGAPI |
| png_process_data(png_structp png_ptr, png_infop info_ptr, |
| png_bytep buffer, png_size_t buffer_size) |
| { |
| if (png_ptr == NULL || info_ptr == NULL) |
| return; |
| |
| png_push_restore_buffer(png_ptr, buffer, buffer_size); |
| |
| while (png_ptr->buffer_size) |
| { |
| png_process_some_data(png_ptr, info_ptr); |
| } |
| } |
| |
| png_size_t PNGAPI |
| png_process_data_pause(png_structp png_ptr, int save) |
| { |
| if (png_ptr != NULL) |
| { |
| /* It's easiest for the caller if we do the save, then the caller doesn't |
| * have to supply the same data again: |
| */ |
| if (save != 0) |
| png_push_save_buffer(png_ptr); |
| else |
| { |
| /* This includes any pending saved bytes: */ |
| png_size_t remaining = png_ptr->buffer_size; |
| png_ptr->buffer_size = 0; |
| |
| /* So subtract the saved buffer size, unless all the data |
| * is actually 'saved', in which case we just return 0 |
| */ |
| if (png_ptr->save_buffer_size < remaining) |
| return remaining - png_ptr->save_buffer_size; |
| } |
| } |
| |
| return 0; |
| } |
| |
| png_uint_32 PNGAPI |
| png_process_data_skip(png_structp png_ptr) |
| { |
| /* TODO: Deprecate and remove this API. |
| * Somewhere the implementation of this seems to have been lost, |
| * or abandoned. It was only to support some internal back-door access |
| * to png_struct) in libpng-1.4.x. |
| */ |
| png_warning(png_ptr, |
| "png_process_data_skip is not implemented in any current version" |
| " of libpng"); |
| return 0; |
| } |
| |
| /* What we do with the incoming data depends on what we were previously |
| * doing before we ran out of data... |
| */ |
| void /* PRIVATE */ |
| png_process_some_data(png_structp png_ptr, png_infop info_ptr) |
| { |
| if (png_ptr == NULL) |
| return; |
| |
| switch (png_ptr->process_mode) |
| { |
| case PNG_READ_SIG_MODE: |
| { |
| png_push_read_sig(png_ptr, info_ptr); |
| break; |
| } |
| |
| case PNG_READ_CHUNK_MODE: |
| { |
| png_push_read_chunk(png_ptr, info_ptr); |
| break; |
| } |
| |
| case PNG_READ_IDAT_MODE: |
| { |
| png_push_read_IDAT(png_ptr); |
| break; |
| } |
| |
| default: |
| { |
| png_ptr->buffer_size = 0; |
| break; |
| } |
| } |
| } |
| |
| /* Read any remaining signature bytes from the stream and compare them with |
| * the correct PNG signature. It is possible that this routine is called |
| * with bytes already read from the signature, either because they have been |
| * checked by the calling application, or because of multiple calls to this |
| * routine. |
| */ |
| void /* PRIVATE */ |
| png_push_read_sig(png_structp png_ptr, png_infop info_ptr) |
| { |
| png_size_t num_checked = png_ptr->sig_bytes, /* SAFE, does not exceed 8 */ |
| num_to_check = 8 - num_checked; |
| |
| if (png_ptr->buffer_size < num_to_check) |
| { |
| num_to_check = png_ptr->buffer_size; |
| } |
| |
| png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]), |
| num_to_check); |
| png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check); |
| |
| if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check)) |
| { |
| if (num_checked < 4 && |
| png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4)) |
| png_error(png_ptr, "Not a PNG file"); |
| |
| else |
| png_error(png_ptr, "PNG file corrupted by ASCII conversion"); |
| } |
| |
| else |
| { |
| if (png_ptr->sig_bytes >= 8) |
| { |
| png_ptr->process_mode = PNG_READ_CHUNK_MODE; |
| } |
| } |
| } |
| |
| void /* PRIVATE */ |
| png_push_read_chunk(png_structp png_ptr, png_infop info_ptr) |
| { |
| png_uint_32 chunk_name; |
| |
| /* First we make sure we have enough data for the 4 byte chunk name |
| * and the 4 byte chunk length before proceeding with decoding the |
| * chunk data. To fully decode each of these chunks, we also make |
| * sure we have enough data in the buffer for the 4 byte CRC at the |
| * end of every chunk (except IDAT, which is handled separately). |
| */ |
| if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER)) |
| { |
| png_byte chunk_length[4]; |
| png_byte chunk_tag[4]; |
| |
| if (png_ptr->buffer_size < 8) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_push_fill_buffer(png_ptr, chunk_length, 4); |
| png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length); |
| png_reset_crc(png_ptr); |
| png_crc_read(png_ptr, chunk_tag, 4); |
| png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag); |
| png_check_chunk_name(png_ptr, png_ptr->chunk_name); |
| png_ptr->mode |= PNG_HAVE_CHUNK_HEADER; |
| } |
| |
| chunk_name = png_ptr->chunk_name; |
| |
| if (chunk_name == png_IDAT) |
| { |
| /* This is here above the if/else case statement below because if the |
| * unknown handling marks 'IDAT' as unknown then the IDAT handling case is |
| * completely skipped. |
| * |
| * TODO: there must be a better way of doing this. |
| */ |
| if (png_ptr->mode & PNG_AFTER_IDAT) |
| png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT; |
| } |
| |
| if (chunk_name == png_IHDR) |
| { |
| if (png_ptr->push_length != 13) |
| png_error(png_ptr, "Invalid IHDR length"); |
| |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| else if (chunk_name == png_IEND) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length); |
| |
| png_ptr->process_mode = PNG_READ_DONE_MODE; |
| png_push_have_end(png_ptr, info_ptr); |
| } |
| |
| #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED |
| else if (png_chunk_unknown_handling(png_ptr, chunk_name)) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| if (chunk_name == png_IDAT) |
| png_ptr->mode |= PNG_HAVE_IDAT; |
| |
| png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length); |
| |
| if (chunk_name == png_PLTE) |
| png_ptr->mode |= PNG_HAVE_PLTE; |
| |
| else if (chunk_name == png_IDAT) |
| { |
| if (!(png_ptr->mode & PNG_HAVE_IHDR)) |
| png_error(png_ptr, "Missing IHDR before IDAT"); |
| |
| else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && |
| !(png_ptr->mode & PNG_HAVE_PLTE)) |
| png_error(png_ptr, "Missing PLTE before IDAT"); |
| } |
| } |
| #endif |
| |
| else if (chunk_name == png_PLTE) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| else if (chunk_name == png_IDAT) |
| { |
| /* If we reach an IDAT chunk, this means we have read all of the |
| * header chunks, and we can start reading the image (or if this |
| * is called after the image has been read - we have an error). |
| */ |
| |
| if (!(png_ptr->mode & PNG_HAVE_IHDR)) |
| png_error(png_ptr, "Missing IHDR before IDAT"); |
| |
| else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && |
| !(png_ptr->mode & PNG_HAVE_PLTE)) |
| png_error(png_ptr, "Missing PLTE before IDAT"); |
| |
| if (png_ptr->mode & PNG_HAVE_IDAT) |
| { |
| if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT)) |
| if (png_ptr->push_length == 0) |
| return; |
| |
| if (png_ptr->mode & PNG_AFTER_IDAT) |
| png_benign_error(png_ptr, "Too many IDATs found"); |
| } |
| |
| png_ptr->idat_size = png_ptr->push_length; |
| png_ptr->mode |= PNG_HAVE_IDAT; |
| png_ptr->process_mode = PNG_READ_IDAT_MODE; |
| png_push_have_info(png_ptr, info_ptr); |
| png_ptr->zstream.avail_out = |
| (uInt) PNG_ROWBYTES(png_ptr->pixel_depth, |
| png_ptr->iwidth) + 1; |
| png_ptr->zstream.next_out = png_ptr->row_buf; |
| return; |
| } |
| |
| #ifdef PNG_READ_gAMA_SUPPORTED |
| else if (png_ptr->chunk_name == png_gAMA) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_sBIT_SUPPORTED |
| else if (png_ptr->chunk_name == png_sBIT) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_cHRM_SUPPORTED |
| else if (png_ptr->chunk_name == png_cHRM) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_sRGB_SUPPORTED |
| else if (chunk_name == png_sRGB) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_iCCP_SUPPORTED |
| else if (png_ptr->chunk_name == png_iCCP) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_sPLT_SUPPORTED |
| else if (chunk_name == png_sPLT) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_tRNS_SUPPORTED |
| else if (chunk_name == png_tRNS) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_bKGD_SUPPORTED |
| else if (chunk_name == png_bKGD) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_hIST_SUPPORTED |
| else if (chunk_name == png_hIST) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_pHYs_SUPPORTED |
| else if (chunk_name == png_pHYs) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_oFFs_SUPPORTED |
| else if (chunk_name == png_oFFs) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| #endif |
| |
| #ifdef PNG_READ_pCAL_SUPPORTED |
| else if (chunk_name == png_pCAL) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_sCAL_SUPPORTED |
| else if (chunk_name == png_sCAL) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_tIME_SUPPORTED |
| else if (chunk_name == png_tIME) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_tEXt_SUPPORTED |
| else if (chunk_name == png_tEXt) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_zTXt_SUPPORTED |
| else if (chunk_name == png_zTXt) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| #ifdef PNG_READ_iTXt_SUPPORTED |
| else if (chunk_name == png_iTXt) |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| #endif |
| |
| else |
| { |
| if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length); |
| } |
| |
| png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; |
| } |
| |
| void PNGCBAPI |
| png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length) |
| { |
| png_bytep ptr; |
| |
| if (png_ptr == NULL) |
| return; |
| |
| ptr = buffer; |
| |
| if (png_ptr->save_buffer_size) |
| { |
| png_size_t save_size; |
| |
| if (length < png_ptr->save_buffer_size) |
| save_size = length; |
| |
| else |
| save_size = png_ptr->save_buffer_size; |
| |
| png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size); |
| length -= save_size; |
| ptr += save_size; |
| png_ptr->buffer_size -= save_size; |
| png_ptr->save_buffer_size -= save_size; |
| png_ptr->save_buffer_ptr += save_size; |
| } |
| |
| if (length && png_ptr->current_buffer_size) |
| { |
| png_size_t save_size; |
| |
| if (length < png_ptr->current_buffer_size) |
| save_size = length; |
| |
| else |
| save_size = png_ptr->current_buffer_size; |
| |
| png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size); |
| png_ptr->buffer_size -= save_size; |
| png_ptr->current_buffer_size -= save_size; |
| png_ptr->current_buffer_ptr += save_size; |
| } |
| } |
| |
| void /* PRIVATE */ |
| png_push_save_buffer(png_structp png_ptr) |
| { |
| if (png_ptr->save_buffer_size) |
| { |
| if (png_ptr->save_buffer_ptr != png_ptr->save_buffer) |
| { |
| png_size_t i, istop; |
| png_bytep sp; |
| png_bytep dp; |
| |
| istop = png_ptr->save_buffer_size; |
| |
| for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer; |
| i < istop; i++, sp++, dp++) |
| { |
| *dp = *sp; |
| } |
| } |
| } |
| |
| if (png_ptr->save_buffer_size + png_ptr->current_buffer_size > |
| png_ptr->save_buffer_max) |
| { |
| png_size_t new_max; |
| png_bytep old_buffer; |
| |
| if (png_ptr->save_buffer_size > PNG_SIZE_MAX - |
| (png_ptr->current_buffer_size + 256)) |
| { |
| png_error(png_ptr, "Potential overflow of save_buffer"); |
| } |
| |
| new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256; |
| old_buffer = png_ptr->save_buffer; |
| png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr, new_max); |
| |
| if (png_ptr->save_buffer == NULL) |
| { |
| png_free(png_ptr, old_buffer); |
| png_error(png_ptr, "Insufficient memory for save_buffer"); |
| } |
| |
| png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size); |
| png_free(png_ptr, old_buffer); |
| png_ptr->save_buffer_max = new_max; |
| } |
| |
| if (png_ptr->current_buffer_size) |
| { |
| png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size, |
| png_ptr->current_buffer_ptr, png_ptr->current_buffer_size); |
| png_ptr->save_buffer_size += png_ptr->current_buffer_size; |
| png_ptr->current_buffer_size = 0; |
| } |
| |
| png_ptr->save_buffer_ptr = png_ptr->save_buffer; |
| png_ptr->buffer_size = 0; |
| } |
| |
| void /* PRIVATE */ |
| png_push_restore_buffer(png_structp png_ptr, png_bytep buffer, |
| png_size_t buffer_length) |
| { |
| png_ptr->current_buffer = buffer; |
| png_ptr->current_buffer_size = buffer_length; |
| png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size; |
| png_ptr->current_buffer_ptr = png_ptr->current_buffer; |
| } |
| |
| void /* PRIVATE */ |
| png_push_read_IDAT(png_structp png_ptr) |
| { |
| if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER)) |
| { |
| png_byte chunk_length[4]; |
| png_byte chunk_tag[4]; |
| |
| /* TODO: this code can be commoned up with the same code in push_read */ |
| if (png_ptr->buffer_size < 8) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_push_fill_buffer(png_ptr, chunk_length, 4); |
| png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length); |
| png_reset_crc(png_ptr); |
| png_crc_read(png_ptr, chunk_tag, 4); |
| png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag); |
| png_ptr->mode |= PNG_HAVE_CHUNK_HEADER; |
| |
| if (png_ptr->chunk_name != png_IDAT) |
| { |
| png_ptr->process_mode = PNG_READ_CHUNK_MODE; |
| |
| if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED)) |
| png_error(png_ptr, "Not enough compressed data"); |
| |
| return; |
| } |
| |
| png_ptr->idat_size = png_ptr->push_length; |
| } |
| |
| if (png_ptr->idat_size && png_ptr->save_buffer_size) |
| { |
| png_size_t save_size = png_ptr->save_buffer_size; |
| png_uint_32 idat_size = png_ptr->idat_size; |
| |
| /* We want the smaller of 'idat_size' and 'current_buffer_size', but they |
| * are of different types and we don't know which variable has the fewest |
| * bits. Carefully select the smaller and cast it to the type of the |
| * larger - this cannot overflow. Do not cast in the following test - it |
| * will break on either 16 or 64 bit platforms. |
| */ |
| if (idat_size < save_size) |
| save_size = (png_size_t)idat_size; |
| |
| else |
| idat_size = (png_uint_32)save_size; |
| |
| png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size); |
| |
| png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size); |
| |
| png_ptr->idat_size -= idat_size; |
| png_ptr->buffer_size -= save_size; |
| png_ptr->save_buffer_size -= save_size; |
| png_ptr->save_buffer_ptr += save_size; |
| } |
| |
| if (png_ptr->idat_size && png_ptr->current_buffer_size) |
| { |
| png_size_t save_size = png_ptr->current_buffer_size; |
| png_uint_32 idat_size = png_ptr->idat_size; |
| |
| /* We want the smaller of 'idat_size' and 'current_buffer_size', but they |
| * are of different types and we don't know which variable has the fewest |
| * bits. Carefully select the smaller and cast it to the type of the |
| * larger - this cannot overflow. |
| */ |
| if (idat_size < save_size) |
| save_size = (png_size_t)idat_size; |
| |
| else |
| idat_size = (png_uint_32)save_size; |
| |
| png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size); |
| |
| png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size); |
| |
| png_ptr->idat_size -= idat_size; |
| png_ptr->buffer_size -= save_size; |
| png_ptr->current_buffer_size -= save_size; |
| png_ptr->current_buffer_ptr += save_size; |
| } |
| |
| if (!png_ptr->idat_size) |
| { |
| if (png_ptr->buffer_size < 4) |
| { |
| png_push_save_buffer(png_ptr); |
| return; |
| } |
| |
| png_crc_finish(png_ptr, 0); |
| png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; |
| png_ptr->mode |= PNG_AFTER_IDAT; |
| } |
| } |
| |
| void /* PRIVATE */ |
| png_process_IDAT_data(png_structp png_ptr, png_bytep buffer, |
| png_size_t buffer_length) |
| { |
| /* The caller checks for a non-zero buffer length. */ |
| if (!(buffer_length > 0) || buffer == NULL) |
| png_error(png_ptr, "No IDAT data (internal error)"); |
| |
| /* This routine must process all the data it has been given |
| * before returning, calling the row callback as required to |
| * handle the uncompressed results. |
| */ |
| png_ptr->zstream.next_in = buffer; |
| png_ptr->zstream.avail_in = (uInt)buffer_length; |
| |
| /* Keep going until the decompressed data is all processed |
| * or the stream marked as finished. |
| */ |
| while (png_ptr->zstream.avail_in > 0 && |
| !(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED)) |
| { |
| int ret; |
| |
| /* We have data for zlib, but we must check that zlib |
| * has someplace to put the results. It doesn't matter |
| * if we don't expect any results -- it may be the input |
| * data is just the LZ end code. |
| */ |
| if (!(png_ptr->zstream.avail_out > 0)) |
| { |
| png_ptr->zstream.avail_out = |
| (uInt) PNG_ROWBYTES(png_ptr->pixel_depth, |
| png_ptr->iwidth) + 1; |
| |
| png_ptr->zstream.next_out = png_ptr->row_buf; |
| } |
| |
| /* Using Z_SYNC_FLUSH here means that an unterminated |
| * LZ stream (a stream with a missing end code) can still |
| * be handled, otherwise (Z_NO_FLUSH) a future zlib |
| * implementation might defer output and therefore |
| * change the current behavior (see comments in inflate.c |
| * for why this doesn't happen at present with zlib 1.2.5). |
| */ |
| ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH); |
| |
| /* Hack, added in 1.5.18: the progressive reader does not reset |
| * png_ptr->zstream, so any attempt to use it after the last IDAT fails |
| * (silently). This allows the read code to do the reset when required. |
| */ |
| png_ptr->flags |= PNG_FLAG_ZSTREAM_PROGRESSIVE; |
| |
| /* Check for any failure before proceeding. */ |
| if (ret != Z_OK && ret != Z_STREAM_END) |
| { |
| /* Terminate the decompression. */ |
| png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; |
| |
| /* This may be a truncated stream (missing or |
| * damaged end code). Treat that as a warning. |
| */ |
| if (png_ptr->row_number >= png_ptr->num_rows || |
| png_ptr->pass > 6) |
| png_warning(png_ptr, "Truncated compressed data in IDAT"); |
| |
| else |
| png_error(png_ptr, "Decompression error in IDAT"); |
| |
| /* Skip the check on unprocessed input */ |
| return; |
| } |
| |
| /* Did inflate output any data? */ |
| if (png_ptr->zstream.next_out != png_ptr->row_buf) |
| { |
| /* Is this unexpected data after the last row? |
| * If it is, artificially terminate the LZ output |
| * here. |
| */ |
| if (png_ptr->row_number >= png_ptr->num_rows || |
| png_ptr->pass > 6) |
| { |
| /* Extra data. */ |
| png_warning(png_ptr, "Extra compressed data in IDAT"); |
| png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; |
| |
| /* Do no more processing; skip the unprocessed |
| * input check below. |
| */ |
| return; |
| } |
| |
| /* Do we have a complete row? */ |
| if (png_ptr->zstream.avail_out == 0) |
| png_push_process_row(png_ptr); |
| } |
| |
| /* And check for the end of the stream. */ |
| if (ret == Z_STREAM_END) |
| png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; |
| } |
| |
| /* All the data should have been processed, if anything |
| * is left at this point we have bytes of IDAT data |
| * after the zlib end code. |
| */ |
| if (png_ptr->zstream.avail_in > 0) |
| png_warning(png_ptr, "Extra compression data in IDAT"); |
| } |
| |
| void /* PRIVATE */ |
| png_push_process_row(png_structp png_ptr) |
| { |
| /* 1.5.6: row_info moved out of png_struct to a local here. */ |
| png_row_info row_info; |
| |
| row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */ |
| row_info.color_type = png_ptr->color_type; |
| row_info.bit_depth = png_ptr->bit_depth; |
| row_info.channels = png_ptr->channels; |
| row_info.pixel_depth = png_ptr->pixel_depth; |
| row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width); |
| |
| if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE) |
| { |
| if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST) |
| png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1, |
| png_ptr->prev_row + 1, png_ptr->row_buf[0]); |
| else |
| png_error(png_ptr, "bad adaptive filter value"); |
| } |
| |
| /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before |
| * 1.5.6, while the buffer really is this big in current versions of libpng |
| * it may not be in the future, so this was changed just to copy the |
| * interlaced row count: |
| */ |
| png_memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1); |
| |
| #ifdef PNG_READ_TRANSFORMS_SUPPORTED |
| if (png_ptr->transformations) |
| png_do_read_transformations(png_ptr, &row_info); |
| #endif |
| |
| /* The transformed pixel depth should match the depth now in row_info. */ |
| if (png_ptr->transformed_pixel_depth == 0) |
| { |
| png_ptr->transformed_pixel_depth = row_info.pixel_depth; |
| if (row_info.pixel_depth > png_ptr->maximum_pixel_depth) |
| png_error(png_ptr, "progressive row overflow"); |
| } |
| |
| else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth) |
| png_error(png_ptr, "internal progressive row size calculation error"); |
| |
| |
| #ifdef PNG_READ_INTERLACING_SUPPORTED |
| /* Blow up interlaced rows to full size */ |
| if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE)) |
| { |
| if (png_ptr->pass < 6) |
| png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass, |
| png_ptr->transformations); |
| |
| switch (png_ptr->pass) |
| { |
| case 0: |
| { |
| int i; |
| for (i = 0; i < 8 && png_ptr->pass == 0; i++) |
| { |
| png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
| png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */ |
| } |
| |
| if (png_ptr->pass == 2) /* Pass 1 might be empty */ |
| { |
| for (i = 0; i < 4 && png_ptr->pass == 2; i++) |
| { |
| png_push_have_row(png_ptr, NULL); |
| png_read_push_finish_row(png_ptr); |
| } |
| } |
| |
| if (png_ptr->pass == 4 && png_ptr->height <= 4) |
| { |
| for (i = 0; i < 2 && png_ptr->pass == 4; i++) |
| { |
| png_push_have_row(png_ptr, NULL); |
| png_read_push_finish_row(png_ptr); |
| } |
| } |
| |
| if (png_ptr->pass == 6 && png_ptr->height <= 4) |
| { |
| png_push_have_row(png_ptr, NULL); |
| png_read_push_finish_row(png_ptr); |
| } |
| |
| break; |
| } |
| |
| case 1: |
| { |
| int i; |
| for (i = 0; i < 8 && png_ptr->pass == 1; i++) |
| { |
| png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
| png_read_push_finish_row(png_ptr); |
| } |
| |
| if (png_ptr->pass == 2) /* Skip top 4 generated rows */ |
| { |
| for (i = 0; i < 4 && png_ptr->pass == 2; i++) |
| { |
| png_push_have_row(png_ptr, NULL); |
| png_read_push_finish_row(png_ptr); |
| } |
| } |
| |
| break; |
| } |
| |
| case 2: |
| { |
| int i; |
| |
| for (i = 0; i < 4 && png_ptr->pass == 2; i++) |
| { |
| png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
| png_read_push_finish_row(png_ptr); |
| } |
| |
| for (i = 0; i < 4 && png_ptr->pass == 2; i++) |
| { |
| png_push_have_row(png_ptr, NULL); |
| png_read_push_finish_row(png_ptr); |
| } |
| |
| if (png_ptr->pass == 4) /* Pass 3 might be empty */ |
| { |
| for (i = 0; i < 2 && png_ptr->pass == 4; i++) |
| { |
| png_push_have_row(png_ptr, NULL); |
| png_read_push_finish_row(png_ptr); |
| } |
| } |
| |
| break; |
| } |
| |
| case 3: |
| { |
| int i; |
| |
| for (i = 0; i < 4 && png_ptr->pass == 3; i++) |
| { |
| png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
| png_read_push_finish_row(png_ptr); |
| } |
| |
| if (png_ptr->pass == 4) /* Skip top two generated rows */ |
| { |
| for (i = 0; i < 2 && png_ptr->pass == 4; i++) |
| { |
| png_push_have_row(png_ptr, NULL); |
| png_read_push_finish_row(png_ptr); |
| } |
| } |
| |
| break; |
| } |
| |
| case 4: |
| { |
| int i; |
| |
| for (i = 0; i < 2 && png_ptr->pass == 4; i++) |
| { |
| png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
| png_read_push_finish_row(png_ptr); |
| } |
| |
| for (i = 0; i < 2 && png_ptr->pass == 4; i++) |
| { |
| png_push_have_row(png_ptr, NULL); |
| png_read_push_finish_row(png_ptr); |
| } |
| |
| if (png_ptr->pass == 6) /* Pass 5 might be empty */ |
| { |
| png_push_have_row(png_ptr, NULL); |
| png_read_push_finish_row(png_ptr); |
| } |
| |
| break; |
| } |
| |
| case 5: |
| { |
| int i; |
| |
| for (i = 0; i < 2 && png_ptr->pass == 5; i++) |
| { |
| png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
| png_read_push_finish_row(png_ptr); |
| } |
| |
| if (png_ptr->pass == 6) /* Skip top generated row */ |
| { |
| png_push_have_row(png_ptr, NULL); |
| png_read_push_finish_row(png_ptr); |
| } |
| |
| break; |
| } |
| |
| default: |
| case 6: |
| { |
| png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
| png_read_push_finish_row(png_ptr); |
| |
| if (png_ptr->pass != 6) |
| break; |
| |
| png_push_have_row(png_ptr, NULL); |
| png_read_push_finish_row(png_ptr); |
| } |
| } |
| } |
| else |
| #endif |
| { |
| png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
| png_read_push_finish_row(png_ptr); |
| } |
| } |
| |
| void /* PRIVATE */ |
| png_read_push_finish_row(png_structp png_ptr) |
| { |
| #ifdef PNG_READ_INTERLACING_SUPPORTED |
| /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ |
| |
| /* Start of interlace block */ |
| static PNG_CONST png_byte FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; |
| |
| /* Offset to next interlace block */ |
| static PNG_CONST png_byte FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; |
| |
| /* Start of interlace block in the y direction */ |
| static PNG_CONST png_byte FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1}; |
| |
| /* Offset to next interlace block in the y direction */ |
| static PNG_CONST png_byte FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2}; |
| |
| /* Height of interlace block. This is not currently used - if you need |
| * it, uncomment it here and in png.h |
| static PNG_CONST png_byte FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1}; |
| */ |
| #endif |
| |
| png_ptr->row_number++; |
| if (png_ptr->row_number < png_ptr->num_rows) |
| return; |
| |
| #ifdef PNG_READ_INTERLACING_SUPPORTED |
| if (png_ptr->interlaced) |
| { |
| png_ptr->row_number = 0; |
| png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); |
| |
| do |
| { |
| png_ptr->pass++; |
| if ((png_ptr->pass == 1 && png_ptr->width < 5) || |
| (png_ptr->pass == 3 && png_ptr->width < 3) || |
| (png_ptr->pass == 5 && png_ptr->width < 2)) |
| png_ptr->pass++; |
| |
| if (png_ptr->pass > 7) |
| png_ptr->pass--; |
| |
| if (png_ptr->pass >= 7) |
| break; |
| |
| png_ptr->iwidth = (png_ptr->width + |
| png_pass_inc[png_ptr->pass] - 1 - |
| png_pass_start[png_ptr->pass]) / |
| png_pass_inc[png_ptr->pass]; |
| |
| if (png_ptr->transformations & PNG_INTERLACE) |
| break; |
| |
| png_ptr->num_rows = (png_ptr->height + |
| png_pass_yinc[png_ptr->pass] - 1 - |
| png_pass_ystart[png_ptr->pass]) / |
| png_pass_yinc[png_ptr->pass]; |
| |
| } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0); |
| } |
| #endif /* PNG_READ_INTERLACING_SUPPORTED */ |
| } |
| |
| void /* PRIVATE */ |
| png_push_have_info(png_structp png_ptr, png_infop info_ptr) |
| { |
| if (png_ptr->info_fn != NULL) |
| (*(png_ptr->info_fn))(png_ptr, info_ptr); |
| } |
| |
| void /* PRIVATE */ |
| png_push_have_end(png_structp png_ptr, png_infop info_ptr) |
| { |
| if (png_ptr->end_fn != NULL) |
| (*(png_ptr->end_fn))(png_ptr, info_ptr); |
| } |
| |
| void /* PRIVATE */ |
| png_push_have_row(png_structp png_ptr, png_bytep row) |
| { |
| if (png_ptr->row_fn != NULL) |
| (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number, |
| (int)png_ptr->pass); |
| } |
| |
| #ifdef PNG_READ_INTERLACING_SUPPORTED |
| void PNGAPI |
| png_progressive_combine_row (png_structp png_ptr, png_bytep old_row, |
| png_const_bytep new_row) |
| { |
| if (png_ptr == NULL) |
| return; |
| |
| /* new_row is a flag here - if it is NULL then the app callback was called |
| * from an empty row (see the calls to png_struct::row_fn below), otherwise |
| * it must be png_ptr->row_buf+1 |
| */ |
| if (new_row != NULL) |
| png_combine_row(png_ptr, old_row, 1/*blocky display*/); |
| } |
| #endif /* PNG_READ_INTERLACING_SUPPORTED */ |
| |
| void PNGAPI |
| png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr, |
| png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn, |
| png_progressive_end_ptr end_fn) |
| { |
| if (png_ptr == NULL) |
| return; |
| |
| png_ptr->info_fn = info_fn; |
| png_ptr->row_fn = row_fn; |
| png_ptr->end_fn = end_fn; |
| |
| png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer); |
| } |
| |
| png_voidp PNGAPI |
| png_get_progressive_ptr(png_const_structp png_ptr) |
| { |
| if (png_ptr == NULL) |
| return (NULL); |
| |
| return png_ptr->io_ptr; |
| } |
| #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */ |
